The present invention generally relates to an ink jet recording head, production methods therefor, and a printer apparatus, and particularly relates to the ink jet recording head which jets ink using jet energy generation part to vibrate a vibrator provided as a wall of a pressure chamber, production methods therefor, and a printer apparatus therewith.
Recently, a printer apparatus has been widely used as an output device for a personal computer. The printer apparatus is generally based on a wire driving method or an ink jet method.
An ink jet recording head used in an ink jet type printer apparatus generates less noise than a head that prints by magnetically driving wires to pressurize a platen through an ink ribbon and a sheet of paper, drawing attention as appropriate for office use.
A conventional ink jet recording head comprises nozzles, ink chambers, ink supply systems, ink tanks and transducers, recording letters and images onto such a recording media as paper by jetting ink particles from the nozzles by transferring displacements or pressures originated at the transducers to the ink chambers.
A widely known method is to use a thin plate of a piezoelectric device that has one surface thereof completely bonded to an external wall of the ink chamber as the transducer. A voltage pulse is applied to the piezoelectric device to bend the compound plate of the piezoelectric device and the external wall of the ink chamber. The displacement/pressure caused by the bend is transferred into the ink chamber through the external wall of the ink chamber.
FIG. 1 is a side view of a printer apparatus (an ink jet recording apparatus) provided with an ink jet recording head 2. In the drawing, a recording media 1 is subjected to printing or the like by the printer apparatus. An ink jet recording head 2 jets ink to the recording media 1. An ink tank 3 provides the ink to the ink jet recording head 2. On a carriage 4, the ink jet recording head 2 and the ink tank 3 are mounted.
A transporting roller 5 and a pinch roller 6 transport the recording media 1 to the ink jet recording head 2 by holding it in between. An ejecting roller 7 and a pinch roller 8 transport the recording media 1 to an ejecting direction by holding it in between. A stacker 9 stores the ejected recording media 1. A platen 10 holds the recording media 1.
The ink jet recording head 2 is so structured as to jet the ink by a pressure generated by expansion and contraction of a piezoelectric device that is driven by a voltage, thereby printing letters or the like on the recording media 1.
FIG. 2 is an oblique angle view of the ink jet recording head 2. As the drawing shows, the ink jet recording head 2 comprises a plurality of piezoelectric devices 11, individual electrodes 12 formed on the piezoelectric devices 11, a nozzle plate 13 that is provided with nozzles 17, a vibrating plate 15, ink chambers (pressure chambers) 14 that are formed corresponding to each of the nozzles 17, and a main body 16 made of a metal or resin.
The nozzle 13 and the vibration plate 15 are designed to face with the ink chamber 14. A portion around the ink chamber 14 of the main body 16 is firmly fixed to the vibrating plate 15. The vibrating plate 15 is so structured as to bend when a voltage is applied to drive the piezoelectric device 11, as shown by the dotted lines in the drawing. Further, the structure allows a voltage to be applied to each of the piezoelectric devices 11 based on electrical signals coming from a printer apparatus main body (not shown in the drawing).
In the conventional ink jet recording head 2, the piezoelectric devices 11 are formed by either pasting plate-like piezoelectric devices 11 on the vibrating plate 15 at a position corresponding to an ink chamber or forming a piezoelectric material on the whole upper surface of the vibrating plate 15 and removing the material except for locations corresponding to the ink chambers to be formed.
In the example shown in FIG. 2, the piezoelectric devices 11 are used as a means to displace the vibrating plate 15. An ink jet recording head that employs thermal elements in place of the piezoelectric devices 11 has been available. The ink jet recording head that employs the thermal elements is structured such that it is provided with thermal elements at the position of the vibrating plate 15 described above, which are made of layers of materials of different thermal expansion coefficients. The thermal expansion generated by heating the elements causes a displacement of the vibration plate 15, and thereby ink is jetted out. In the following, an item that generates energy to displace the vibrating plate 15, which includes the piezoelectric elements 11 and thermal elements described above will be called an ink jet energy generating part.
In recent years, there has been a demand for reducing the power consumption of personal computers. Accordingly, reduced power consumption (semiconductor driving voltage of around 20V) is required of printing devices serving as peripheral equipment. Furthermore, higher resolution is required of the printing devices, so that flight particles of the ink jet recording head are made finer and finer.
Specifically, following requirements need to be satisfied to achieve what is required above. That is, in the case of using a piezoelectric element for the ink jet energy generating part:
a) thin-filming of the piezoelectric element (same internal applied electric field);
b) thin-filming of the vibration plate (transferring a minute displacement of the piezoelectric element);
c) stable adherence of the piezoelectric element to the vibrating plate (reducing loss of piezoelectric element displacement);
d) higher flatness of the vibrating plate (ease of bending the vibrating plate); and
e) a minute process of the piezoelectric device and the vibrating plate are required.
In the case of using the thermal element in the ink jet energy generating part,
f) finer wiring of wires connected to the thermal element;
g) shorter heat dissipation time; and
h) thinner protection films of the thermal devices are required.
In the conventional ink jet recording head 2 described with reference to FIG. 2, following problems are present. Namely, in the structure where the piezoelectric device is bonded to the vibrating plate,
1) a thin piezoelectric element is susceptible to damages when the piezoelectric device is bonded to the vibrating plate;
2) in the structure where the piezoelectric device is bonded to the vibrating plate, thickness of an adhesive material layer is non-uniform, causing difficulties to obtain a flat vibrating plate, and thereby cases happen wherein it does not displace properly when driven;
3) an adhesive material absorbs displacement of the piezoelectric element when a voltage is applied to the piezoelectric element; and
4) miniaturization is difficult with the structure where the piezoelectric element is bonded to the vibrating plate.
Further, in a structure in which a piezoelectric material provided all over the vibrating plate is divided by a machine process, the problems 1) through 4) described above are encountered in the same manner. Furthermore, the machine process presents problems that it takes a longer processing time and provides a less production efficiency.
When the thermal element is used in the ink jet energy generating part, the board that carries the thermal element thereon may not have proper heat releasing characteristics.
The present invention is made in view of the points described above with an object to provide an ink jet recording head and production methods therefor and a printer apparatus which hold a high reliability while enabling to reduce consumption power.
To achieve the object, the present invention takes a structure wherein at least an ink energy generating part employs the thin film forming technology in an ink jet recording head that comprises a main part that is formed by a plurality of pressure chambers which are provided corresponding to nozzles that spout the ink and in which ink is filled, a vibrating plate that is formed by a vibratable material and is a part of a wall of the pressure chambers described above, and an ink jet energy generating part that is provided on the vibrating plate described above corresponding to the pressure chambers described above and that causes the nozzles described above to spout ink from the pressure chambers described above by deformatively energizing the vibrating plate described above.
Such an inkjet record head makes it possible to form a thin and fine inkjet energy generating part with high precision and reliability by employing a thin-film production technology in making the inkjet energy generating part. This achieves the reduction of power consumption and the printing of higher resolution.
Further, to achieve the present invention, in the ink jet recording head production method, an energy generating part forming step wherein the ink jet energy generating parts are formed by forming an individual electrode layer, an energy generating layer and a vibration layer sequentially on a base plate using the thin film forming technology, a removal step wherein the ink jet energy generating parts described above are exposed from the base plate described above by forming an opening part by removing an part that corresponds to a deforming portion of at least a the ink jet energy generating part described above, and a bonding step wherein a main component pre-formed with pressure chambers for jetting ink and the described vibrating plate part bonded, and a nozzle installation step wherein nozzle holes that spout ink are formed at positions corresponding to the described pressure chambers and at the same time a nozzle plate is provided on the described main component are performed.
By the ink jet recording head production method described above, a thin ink jet energy generating part can be formed with a high accuracy and a high reliability, because the individual electrode layer, the energy generating layer and the vibrating layer are formed sequentially on the base plate using the thin film forming technology.
Further, because there is no bonding materials such as an adhesive material between the layers, it is possible to form the ink jet energy generating part with high flatness, and thereby there is no absorption of a displacement of a piezoelectric element by the adhesive material, as was the case conventionally. Therefore, an ink jet recording head with a potentiality of a reduced power consumption and a high resolution can be realized.
Further, in the removal step, the ink jet energy generating parts are exposed from the base plate by forming an opening part by removing a predetermined part of the base plate, a part other than the exposed part keeps protected by the base plate. Therefore, the protection is dependably performed when the ink jet energy generating part is made thin.
Subsequently, by performing the bonding step and the nozzle plate installation step, the ink jet energy generating part described above is bonded to the main body which is formed with pressure chambers. In this manner, a flat vibrating plate can be provided to the pressure chambers, enabling production of an ink jet recording head whose piezoelectric elements are closely bonded to the vibrating plate and which can be driven efficiently and without unevenness.
The present invention, in the ink jet recording head production method described above, may structure the described bonding step by comprising a first bonding step wherein a first half of the main component pre-formed by a first half of the pressure chambers on the vibrating layer mentioned above for ink jetting, which is performed between the described energy generating part forming step and the described removal step and a second bonding step wherein a second half of the main body component pre-formed by a second half of the pressure chambers for ink jetting is bonded to the described first half of the main component after the described removal step is finished.
By the ink jet recording head production method above described, between the energy generating part forming step and the removal step, that is, before the removal step is performed, the first bonding step is performed. By bonding the first half of the main body formed with the first half of the pressure chambers onto the vibrating layer, the base plate is structured as reinforced by the first half of the main body component.
Accordingly, when an opening part is formed during the removal step, there is the first half of the main component on the rear side of the opening part forming location, thereby preventing a damage of the ink jet energy generating part when the opening part is formed. Further, by forming the opening part, mechanical strength of the ink jet energy generating part that is exposed from the opening part is weakened, however, thanks to the presence of the first half of the main component that functions as a reinforcement material on the rear side of the opening part forming position, whereby preventing a damage of the ink jet energy generating part after the opening part is formed.
Further, the main body is formed by performing the second bonding step after the removal step, thereby bonding the second half of the main component formed by the second half of the pressure chambers, and through a cooperation between the first and the second halves of the pressure chambers.
Further the present invention can be structured in the ink jet recording head production method described above such that the described energy generating part forming step may take a dividing step wherein the individual electrodes are formed by dividing the described individual electrode layer at the forming position of the described ink jet energy generating part, after the described individual electrode layer is formed and before the described energy generating layer is formed.
According to the ink jet recording head production method described above, the individual electrodes can be formed easier than the method wherein the individual electrode layer is divided via the opening part, because the individual electrodes are formed before the opening part is formed by performing the dividing step after the individual electrode layer is formed and before the energy generating layer is formed to form the individual electrodes by dividing the individual electrode layer at the forming position of the ink jet energy generating part.
Further, the present invention, in the ink jet recording head production method, can provide a dividing step wherein the individual electrodes are formed by the energy generating part forming step described above through dividing both the individual electrode layer described above, which is exposed to the opening part described above, and the energy generating layer at the forming position of the ink jet energy generating part described above after the removal step described above is finished.
According to the ink jet recording head production method described above, by performing the dividing step after the removal step is finished, and by forming the individual electrodes by dividing both of the individual electrode layer exposed at the opening part and the energy generating layer at forming position of the ink jet energy generating parts, the adjacent ink jet energy generating parts become a perfectly independent structure. Accordingly a deforming capability (drivability) of the ink jet energy generating parts when a voltage is applied is enhanced, thereby a mechanical mutual interaction among the adjacent ink jet energy generating parts is low, enabling a highly responsive ink jetting.
Further, the present invention can be structured in the ink jet recording head production method such that it has a dividing step wherein the individual electrodes are formed by dividing only the individual electrode layer exposed to the opening part described above at the ink jet energy generating part forming position after the removal step described above is finished.
By the ink jet recording head production method described above, the ink jet energy generating part with a small amount of an internal distortion can be structured, because the individual electrodes are formed by dividing only the individual electrode layer exposed to the opening part at the described ink jet energy generating part forming position.
That is, in a dividing step wherein the individual electrodes are formed by dividing before the energy generating layer is provided, when the energy generating layer is formed, there emerge a portion where the energy generating layer is deposited directly on the base plate and another portion where the energy generating layer is deposited on the individual electrodes. Due to this, the energy generating layer is susceptible to an internal distortion caused by crystal growth unevenness, difference in lattice constants or the like from damages to the base board at the individual electrode removal. If the opening part is formed on the base board under this situation, damages (cracks and deformation) can happen at the boundaries of the individual electrodes due to the internal distortion at the thin film part after the removal.
Whereas, by forming the individual electrode layer on the whole surface of the base board as well as the energy generating layer is formed thereupon, and then performing the dividing step of dividing the individual electrode layer via the opening part after the removal step is finished, the ink jet energy generating part with a small amount of the internal distortion can be formed, thereby enabling to enhance a reliability of the ink jet recording head to be manufactured.
Further, the present invention, in the ink jet recording head production method described above, the ink jet energy generating part described above can be formed over a plurality of pressure chambers described above in the energy generating part forming step described above.
According to the ink jet recording head production method described above, strength of the ink jet energy generating part can be enhanced by forming the ink jet energy generating part over a plurality of the pressure chambers in the energy generating part forming step.
That is, if the ink jet energy generating part is formed in the forming part of the pressure chambers, the structure is such that the ink jet energy generating part is supported only by a thin vibrating plate, reducing the strength, because the pressure chambers are vacant parts. Whereas, by forming the ink jet energy generating part over a plurality of pressure chambers, the ink jet energy generating part is supported by the peripheral part of the base plate, thereby enhancing the strength of the ink jet energy generating part.
Further, to achieve the object described above, the ink jet recording head production method of the present invention performs an energy generating part forming step wherein the ink jet energy generating parts are formed by forming an energy generating layer that makes the ink jet energy generating part and a vibration layer sequentially on the base plate using the thin film forming technology, a removal step wherein the described ink jet energy generating parts are exposed from the described base plate by forming an opening part by removing an part that corresponds to a deforming portion of at least the described ink jet energy generating part, an individual electrode forming step wherein the individual electrodes are formed at positions corresponding to the described ink jet energy generating part via the described opening part after the removal step is finished, and an bonding step wherein a main component that is formed in advance with pressure chambers for jetting ink is bonded to the described vibration plate.
According to the ink jet recording head production method described above, the energy generating layer can be grown in a monocrystal condition according to the lattice constant of the base plate (the lattice constant is not uniform, but has an internal distortion), by forming the energy generating layer that will become the ink jet energy generating part and the vibrating layer sequentially on the base plate using the thin film forming technology.
Now, if there is a metal electrode layer (individual electrode layer) without a crystal lattice is present between the base plate and the energy generating layer, when the energy generating layer is formed, there is a case where its lattice may be deformed, disabling to obtain a good jetting energy.
Whereas, by forming the individual electrodes by performing the individual electrode forming step on the surface of the energy generating layer that is exposed from the opening part after the opening part is formed on the base board in the removal step, it is possible to form the ink jet energy generating part that has a required lattice constant, enabling to obtain a good jetting energy. Therefore, highly reliable printing process is enabled.
Further, the present invention, in the ink jet recording head production method described above, the dividing position where the dividing process described above is performed in the dividing step described above may be set at a position between pressure chambers described above that are next to each other.
According to the ink jet recording head production method described above, protection of the vibrating plate can be secured by setting the dividing position of the dividing process for the individual electrode layer in the dividing step at a position between adjacent pressure chambers.
That is, because the pressure chamber is a vacant part, the structure of the ink jet energy generating part (including the individual electrode layer) is such that it is supported only by the thin vibrating plate. Therefore, there is a possibility of a crack and other damage developing to the vibrating plate if the individual electrode layer dividing step takes place in the forming part of the pressure chambers.
Whereas, by setting the dividing position of the individual electrodes at a position between the adjacent pressure chambers, the dividing position is not the pressure chambers but on the base board, thereby the structure is such that the ink jet energy generating part is formed over the pressure chambers, enabling a secure protection of the vibrating plate.
Further, to achieve the object described above, the ink jet recording head production method of the present invention performs: the individual electrode forming step where in the individual electrode layer is formed on the base plate using the thin film forming technology; the individual energy generating layer forming step wherein individual energy generation layer is formed at least on the individual electrode layer described above; a filling step wherein a filler material is provided to a gap between the individual energy generation layers described above which are formed in the individual energy generating layer forming step described above; the energy generating part forming step where in the ink jet energy generating part is formed by performing a vibrating layer forming step wherein a vibrating layer is formed above the individual energy generating layer described above and the filler material described above; the removal step wherein the ink jet energy generating part described above is exposed from the base plate described above by forming an opening part by removing at least an part corresponding to the deforming portion of the ink jet energy generating part described above of the base plate described above; and the bonding step wherein the main body component that is formed in advance with pressure chambers for ink jetting is bonded to the vibrating plate described above.
According to the ink jet recording head production method described above, by providing the filler material to the gap between the ink jet energy generation parts, a structure that is flat and free from bending is obtained, thereby enabling a smooth ink jetting.
That is, if the vibrating plate is formed on the ink jet energy generating part that has unevenness without the filler material, a bent of the vibrating plate occurs at a bump of the unevenness, which binds deformation of the ink jet energy generating part, causing a possibility to create a hindrance in ink jetting.
Whereas, by providing the filler material to the gap between the ink jet energy generating parts at the filling step, its surface is flattened and forming the vibrating plate on the flat surface, a structure that is flat and free from a bent is obtained. In this manner, by making the structure free from the bent, a smooth ink jetting is enabled.
Further, the present invention may use the same material as the base plate described above as the filler material described above in the ink jet recording head production method described above.
According to the ink jet recording head production method described above, by using the same material as the base plate as the filler material, when the opening part is formed in the removal step to be performed later, the filling material in the gap of the ink jet energy generating part is removed simultaneously. For this reason, each ink jet energy generating part has an independent structure, thereby drivability of the ink jet energy generating part can be enhanced.
Further, the present invention may use a material whose Young""s modulus is smaller than the energy generating layer described above and less than 90 GPa as the filler material in the ink jet recording head production method described above.
According to the ink jet recording head production method described above, by using a material with a low Young""s modulus as the filler material, the ink jet energy generating part""s deformation (displacement) will not be restricted by the filler material if the filler material is provided in the gap of the ink jet energy generating parts, enabling a sure ink jetting.
Further, the present invention may use a material that has elastic and anti-ink properties as the filler material described above in the ink jet recording head production method described above.
According to the ink jet record head production method described above, by using a material that has elastic and anti-ink properties as the filler material, an ink leakage from the pressure chamber is protected by the filler material.
That is, in a rare case, a pinhole or the likes are formed in the vibrating plate that is exposed from the opening part by performing the removal step. In this case, the ink in the pressure chamber oozes from the pinhole, causing a fault such as a shorted circuit or the like at an electric part of the ink jet energy generating part (piezoelectric element). Whereas, even if there is a pinhole in the vibrating plate, it is acceptable if it functions without a problem, ink-oozing prevented.
Therefore, by providing the filler material that has elastic and anti-ink properties between the ink jet energy generating parts in the opening part, ink oozing is protected without hindering the driving (deformation, displacement) of the ink jet energy generating part.
Further, the present invention may perform the removal step described above after the bonding step described above in the ink jet recording head production method.
According to the ink jet recording head production method described above, b performing the removal step after the bonding step is finished, when the opening part is formed in the removal step, the status of the rear side of the base plate is such that it is bonded to the main body. For this reason, when the opening part is formed, the ink jet energy generating part formed on the base board is protected from damages, enabling to enhance yields and reliability.
Further the present invention may perform the nozzle plate installation step either before or after the bonding step described above in the ink jet recording head production method.
Further the present invention may additionally perform a heat dissipation part forming step wherein a material with a high heat conductivity is provided at the opening part formed on the base plate described above after the removal step described above in the ink jet recording head production method described above.
According to the ink jet recording head production method described above, by providing a material with a high heat conductivity at the opening part formed on the base plate through the heat dissipating part forming step after the removal step, an efficient heat dissipation of heat generated at the ink jet energy generating part is enabled, thereby enabling a high-speed printing.
Further, to achieve the object described above, the present invention may take a structure in the ink jet recording head that spouts ink from the pressure chamber, wherein the piezoelectric element is provided, which is formed by a growth step in which the piezoelectric element is grown on the base plate using the thin film forming technology, and a removal step in which the base plate of the deforming part of the piezoelectric element described above is removed, while leaving the base plate at the peripherals of deforming part of the piezoelectric element described above.
Further, to achieve the object described above, the present invention may take a structure wherein an ink jet recording head is provided, which uses a piezoelectric element that is formed by the growth step in which the piezoelectric element described above is formed on the base plate using the thin film forming technology and the removal step in which the deforming part of the piezoelectric element described above of the base plate is removed, while leaving the base plate at the peripherals of the deforming part of the piezoelectric element described above, in a printer apparatus that uses an ink jet recording head that spouts the ink from the pressure chamber described above by deforming the piezoelectric element by an electrical signal, comprising a pressure chamber and a piezoelectric element.